Abstract: Centralizer apparatuses attached around a unison ring include rub buttons at inner ends of stud attached to and spaced apart from the unison ring and include rolling bearings. Each rolling bearing rotatably trapped within bearing chamber in bearing receptacle at inner end of stud. Tip cap includes bearing aperture trapping rolling bearing within bearing chamber. Rolling bearing extends partially through bearing aperture. Rolling bearing may be spring loaded within chamber by spring between the bearing receptacle and the rolling bearing. Stud may extend through and may be threaded into mounting aperture in unison ring and nut may be threaded onto outer end of stud. Variable stator vanes rotatably mounted to a casing and connected to vane crank arms connected to the unison ring mounted exterior to casing.

Abstract: Centralizer apparatuses attached around a unison ring include rub buttons at inner ends of stud attached to and spaced apart from the unison ring and include rolling bearings. Each rolling bearing rotatably trapped within bearing chamber in bearing receptacle at inner end of stud. Tip cap includes bearing aperture trapping rolling bearing within bearing chamber. Rolling bearing extends partially through bearing aperture. Rolling bearing may be spring loaded within chamber by spring between the bearing receptacle and the rolling bearing. Stud may extend through and may be threaded into mounting aperture in unison ring and nut may be threaded onto outer end of stud. Variable stator vanes rotatably mounted to a casing and connected to vane crank arms connected to the unison ring mounted exterior to casing.